@stoned,

I believe the responsible program is "osso-startup-wizard". It is run from /etc/X11/Xsession.d/30sso_startup_wizard

I actually moved the file away to get rid of it, but I haven't actually tested it fully (I never swapped the SIM card, and I never remove the battery . But for sure the N900 boots fine.

A less drastic option may be to create an empty file called "dont_start_suw" and put in on the /var directory (the above script checks for existance of this file, and if so, doesn't do anything).

You might also want to uninstall the "osso-startup-wizard" package (nothing depends on it).

Just be prepared to reflash if you do any of the above. If you do, then please report back.